Our forum member Caius has yet again shared very valuable information for X68000 Compact owners.
Primarily in Japan there are 3,5“ floppy drives that support 3 modes of disk formats - 1.44MB, 1.25MB and 720kB. Hence the name “Floppy 3 mode”. The X68000 3.5” floppy drives spin at 360RPM and support 1.25MB but IBM PC 3.5“ drives at 300RPM and do not support 1.25MB format. That is why it is absolutely necessary to have a 3mode floppy drive. It is recommended to use USB models and Sony Vaio PCGA-UFD5 floppy drive was used for this test. It is very cheap and can be purchased from here:
Here is a list of some USB floppy drives with 3mode support:
Here is a list of internal slim floppy drives with 3mode support:
Sadly Omniflop doesn't work with USB floppy drives so first you have to format correctly the 3.5 HD floppy with this DOS command:
or this one if the previous doesn't work:
a: is the letter assignment to the floppy drive. It can change to b: or other, depending on your hardware configuration.
If you can't format a 3,5 floppy disk at 1.2 MB with these DOS commands, try this trick. First format the disk at 1.44 MB (using Windows utility) and then format it at 1.2 MB with the DOS command. Sometimes it can help.
After you have formated the 3.5 floppy disk, you can write back disk images using DiskImage 1.3b Utility:
These are the correct settings:
You can do a low-level format of the floppy into 1.2MB mode with ufiformat:
After that, disk images can be written as normal. XDF files are bare images, so you can write them with e.g. dd:
3.5” floppies can also be written with USB flux imaging hardware. See writing_floppies for details.